Aggregation in Blattaria1

When given a choice between contaminated vs. uncontaminated paper, young nymphs of several species of cockroaches will aggregate on paper contaminated by own or another species. In a few instances a species (e.g., Blattella germanica [L.]) may be repelled the fouling of another species ( Sytnploce capitata [Saussure] and Diploptera punctata [Eschscholtz]). Usually a species can discriminate between and prefers own fecal contamination to that of others. One cannot assume that all species of cockroaches produce a fecal aggregation pheromone simply because other species collect on paper contaminated by them. When the nymphs of 2 different species were tested in 32 combinations in a chamber with 8 shelters, 17 combinations segregated, 10 were more or less indifferent to one another, and 5 integrated (mixed). Mixing of 2 species occurred mainly within the Blaberinae and Oxyhaloinae, but 7 of the 9 species tested belonged to these 2 subfamilies.